ABSTRACT ? Administrative Core The purpose of this Collaborative Program is to bring together investigators focusing on a coordinated and synergistic strategy within the overarching goals of the Nonhuman Primate Transplantation Tolerance Cooperative Study Group (NHPCSG), including: (1) development of novel tolerance induction regimens; (2) evaluation of the preclinical safety and efficacy of existing and newly developed candidate immune tolerance induction regimens; (3) development and validation of biomarkers for the induction, maintenance and/or loss of immune tolerance or for the prediction of graft rejection; and (4) elucidation of the mechanisms underlying the induction, maintenance, and/or loss of tolerance in NHP allograft models of islet, kidney, heart, and/or lung transplantation. In order to coordinate our program's efforts to achieve these goals, we propose an Administrative Core to manage fiscal and other resources, facilitate interactions and communication, ensure timely progress toward program goals, and ensure adherence to NIH regulations regarding management of the grant.